1. Field of the Invention
The present invention relates to an amplification apparatus that reduces power consumption during silence.
2. Description of the Related Art
In Japanese Patent Application Laid-Open No. 7-226633, there is described a technique of detecting an output signal of an amplifier and driving a fan to cool the amplifier when the output signal of the amplifier is high, thereby protecting the amplifier. In Japanese Patent Application Laid-Open No. 2008-118825, there is described a technique of detecting an output signal of an amplifier and switching a power-supply voltage supplied to the amplifier from a high voltage to a low voltage to protect the amplifier, when the output signal of the amplifier is high.
Moreover, in Japanese Patent Application Laid-Open No. 8-242124, there is described a technique of putting a power-supply voltage supplied to the amplifier into an off state when an audio signal inputted to am amplifier is lower than a reference voltage, thereby reducing power consumption during silence. According to this technique, a detection circuit that detects the presence or absence of the audio signal inputted to the amplifier needs to be provided between an audio input terminal and the amplifier, which disadvantageously increases a circuit size, thereby increasing a cost. In the case of an AV amplifier including a plurality of audio input terminals, a detection circuit that detects the presence or absence of the audio signal for each of the plurality of audio input terminals needs to be provided, which further increases the circuit size, thereby further increasing the cost.